Purpose The purpose of this paper is to use social identity theory and the elaboration likelihood model to explore differences in consumer response to positive and negative online brand advertising based on the degree to which the consumer identifies with the brand featured in the ad. Dependent variables include attitude toward the ad, attitude toward the brand, willingness to share the ad and purchase intention. Design/methodology/approach This study uses a posttest-only, 2 (low consumer–brand identification v. high consumer–brand identification) × 2 (negative advertisement v. positive advertisement) between-subjects factorial design for two separate brands based on the pretest results. Findings Results show, in support of extant research, that consumer–brand identification enhances consumer perceptions of positive brand advertising. In addition, this research shows that consumer–brand identification also minimizes the potentially detrimental effects of negative advertisements on the dependent variables. Further, results suggest that those with a low consumer–brand identification are more likely to share negative online brand advertising. Practical implications Building consumer–brand identification among target consumers results in positive brand attitudes and behaviors while at the same time shielding brands from negative online attack advertising. However, consumers with weak consumer–brand identification can be influenced through peripheral cues in online ads. This research indicates that managers need to focus on strengthening consumer–brand identity with target audiences and closely monitor negative online sentiment. Originality/value This exploratory research extends current consumer–brand relationship scholarship and adds support for application of the elaboration likelihood model in an online environment. To the best of the authors’ knowledge, this study is the first to examine the role of consumer–brand identity and its role in explaining consumer responses to online display advertising.